Injector sealing washer thicknesses?

[aspoonhour]

I did a search for this, but did find what I was looking for...

What are the different thicknesses of copper injector sealing washers for? I noticed that the PDR website recommended the "thinnest" washer for their "190's". I was told that it is similar to advancing timing. I just reinstalled my stock injectors with a slightly thinner washer than the stock ones (noticed after the install) and wondered if this was a bad idea and should I change them back.

I think that this might the precursor, to a lengthy discussion that I missed...

Thanks in advance.

Andrew.

PS...If anyone want to here the whole "comedic" story, let me know. It's sort of like "1st gen's - 101" if you read it backwards...

[dpuckett]

The thinnest 12v washers you can get are .020". Stock intercooled washers are ~.090"- pretty thick. There are also some .060" that split the difference.

I dont see how some people believe that placing the injector tip farther down in the combustion bowl will have the same efect as advancing the timing- the fuel gets injected at the same time. You just place the fuel spray farther down from the head, which may or may not help smoke. My mom's 92 actually smoked MORE with the thinner (.060) washers than with the stock .090s. I've never noticed a difference in power or mileage by swapping washers.

Dan

[aspoonhour]

Daniel. Thanks...I haven't really noticed a difference, but wanted to make sure there wasn't a mechanical issue with using a thinner washer.

Thanks
Andrew

[PToombs]

I put .020s in with my 370's. I checked at work to see what we had before I put them in, .020, .040, .080.
It must work, they only haze when it's cold. Once it's warm, nothing.

[aspoonhour]

Thanks Pete!!!

Andrew

[fergavs]

By lowering the injectors into the fuel bowl the fuel hits the piston "sooner". This happens at a ever so slight time sooner then it does with thicker washers. I am not an engineer so I could not state the clear benefit or faults of using the thinner washers but can understand why people state it is like advancing the timing. When you advance the timming the fuel hits the fuel bowl in the piston "sooner" just like using the thinner washer. Yes the fuel gets sprayed in at the same "time" but it is in the bowl a few degrees "sooner" from top dead center. I could see that this could give the same benefits as advancing the timing.

[aspoonhour]

Thanks Fergavs! That makes sense too...Hmmm...This is interstesting...What else?

Andrew

[cell]

I'm getting my stock IC injectors pop tested so I got all new return line banjo washers, injector nut orings and copper crush washers. The new copper injector washers cummins gave me are much thinner than the ones I took out. Maybe there is an advantage to having thinner washers?

[BC847]

It's my understanding that ~
- With advancing the fuel injection pump as we often do, the timing of the beginning of the injection event relative to the piston position (ie: The injector nozzle relative to the piston bowl), is changed such the the fuel starts squirting slightly before the piston bowl is in the best position to receive the fuel.

By using thinner washers, the injector nozzle is moved closer to the piston bowl considering the new injection event timing/bowl thing, perhaps better optimizing things in that regard.



Clear as mud?

[fasttalker83]

I know from some problems John deere had back when they came out with the 4430 they had a really thin crush washer in from the factory and made the tractors hard to start and smoke and for the price of 6-18cent washers that were a thicker washer the tractors became really easy to start and didnt even have a haze to them I had a Deutz tractor at one of my auctions that a man rebuilt and left the washers out-it was most smoke I had seen out of any tractor that had been rebuilt only 3yrs before the guy didnt think he needed them in there-theres a little insight on some crush washer expeirences if it helps

[BC847]

These are solid soft copper. And with only 42 ft/lbs on the retaining nuts, there's not a whole lot of crush if any (as in crush-washer). The copper is just soft enough for a good seal.


(0.020" Shown)

[SChandler]

I would assume the different washer thicknesses are for tuning purposes. Every motor/injector combo is different, so different combos will require different tuning to make it haze/not haze, etc. You can't make a rule saying that you always want the thick or thin washers. Every motor responds different. There will be trends, but run a set of marine 370's, New Era 370's or DDP Stage 4's in the same motor and I bet each one would perform best with a slightly different thickness washer. Stock injectors - I would go with stock thickness washers. Aftermarket injectors - start with whatever the injector manufacturer recommends and tune from there.